Generally, a washing machine is an apparatus providing a mechanical action using electricity, thereby removing dirt from clothes. When the clothes are put into water containing a detergent dissolved therein, dirt is removed from the clothes by a chemical action of the detergent. However, since it takes a long time to remove the dirt from the clothes by the chemical action of the detergent alone, the dirt can be easily removed from the clothes by forcibly generating a rotary current or applying a mechanical action such as friction or vibration to the clothes.
The washing machine comprises an outer tub, an inner tub rotatably placed in the outer tub for containing clothes, a wash vane rotatably installed in the inner tub for generating a washing current, and a motor and a clutch installed below the lower part of the outer tub for rotating the inner tub or the wash vane.
The above washing machine has different washing or rinsing capacities based on the quantity of the clothes, the quantity of the detergent, and the hardness of wash water. In a conventional control method of the washing machine, the quantity of the clothes placed into the inner tub is sensed, a washing pattern including washing time, rinsing frequency, rinsing time, dehydrating time, etc. is set based on the sensed quantity of the clothes, and the washing machine is operated according to the set washing pattern.
However, the conventional control method of the washing machine considers only the quantity of the clothes while disregarding the hardness of the water supplied to the washing machine, thus causing a limit in improving washing or rinsing capacity of the washing machine.